The present invention relates to a method for controlling a reversible belt tensioner of a safety belt in a motor vehicle. In addition, the present invention relates to a driver assistance system for a motor vehicle. Finally, the present invention relates to such a vehicle.
Today's vehicles are equipped with a conventional belt system without a reversible belt tensioner or with a belt system with a reversible belt tensioner. For motor vehicles that are equipped with reversible belt tensioners, the safety belt is tightened at the beginning of a trip when the belt is inserted and the so-called belt slack is removed. However, slack can be introduced again into the respective safety belt system during the trip by movement of the driver or of the passenger or as a result of a driving maneuver. The safety belt is then no longer sufficiently tightened and the safety of the driver or of the other vehicle occupants is no longer fully guaranteed.
DE 10 2005 035 850 A1 relates to a method for controlling a reversible belt tensioner in a motor vehicle, wherein the time profile of a measured value characterizing the vehicle dynamics is determined and a gradient of this measured value is calculated. The belt tensioner is activated when the gradient of the measured value exceeds a predetermined threshold value.
DE 10 2005 035 863 A1 describes a method for controlling a reversible belt tensioner in a motor vehicle. In this case, the belt tensioner is activated, so that a safety belt is brought from a normal position to a second position wherein the belt is tightened more than in the normal position. The belt tensioner is here activated independent of any dangerous situation.
DE 10 2008 050 316 A1 discloses a method for dynamically securing a vehicle occupant strapped in a seat of the vehicle with a safety belt. Here, a transverse dynamics of the vehicle is determined by at least one sensor. A slack of the safety belt is then at least partially rolled up by a safety belt retractor, when an upper threshold value of the transverse dynamics is exceeded, and a radius of curvature of a road course ahead remains constant or decreases.
DE 10 2008 007 149 A1 describes a method for generating, controlling and triggering a warning signal in a motor vehicle. Here, an attentiveness measure of the driver is determined by analyzing the driver's eye blink. A corresponding warning signal is outputted, for example by activation of the belt tensioner, in response to the attentiveness.
Lastly, systems are used in modern motor vehicles, wherein the field of vision of the driver is monitored by a camera. For example, when the driver turns his eyes away from the road and the driver assistance system recognizes a corresponding obstacle on the road, the driver is warned visually or audibly. However, the installation of such systems results in additional costs.